Warfarin D/C Within 180 Days Post-Surgery May Up Mortality

CV death risk up with warfarin discontinuation within six months of valve replacement

TUESDAY, Nov. 27 (HealthDay News) -- Patients who undergo bioprosthetic aortic valve replacement surgery and discontinue anticoagulant treatment within six months have a greater risk of cardiovascular death, according to a study published in the Nov. 28 issue of the Journal of the American Medical Association.

Charlotte Mérie, M.D., from the Copenhagen University Hospital Gentofte in Denmark, and colleagues analyzed outcomes data based on warfarin use from 4,075 patients in Denmark without atrial fibrillation who had bioprosthetic aortic valve replacement surgery from 1997 to 2009.

During a median follow-up of 6.57 person-years, the researchers found that the adjusted incidence rate ratios (IRRs) were higher in patients who did not receive warfarin: 2.46 for stroke, 2.93 for thromboembolic events, and 2.32 for bleeding incidents. In addition, the IRR was 7.61 for cardiovascular deaths when warfarin was discontinued within 30 to 89 days after surgery and 3.51 for cardiovascular deaths when warfarin was discontinued within 90 to 179 days after surgery.

"The novelty of our study is the finding that discontinuing warfarin therapy within 90 to 179 days after surgery is associated with a significant increase in the risk of cardiovascular death," Mérie and colleagues conclude. "Consequently, our study challenges current guidelines on the duration of antithrombotic treatment after aortic valve replacement surgery with biological valves by presenting results suggesting that these patients will gain from an additional three months of warfarin treatment in terms of reduced cardiovascular death without risking a significant increase in bleeding events."